Funeral For Family Gassed To Death Was Held Today

They died in the most tragic circumstance, but there was no room for judgment as the Lutz-Manrique family were finally laid to rest two weeks after their suspected murder-suicide in Sydney.

Instead it was the "unending commitment" by both Maria Lutz, 43, and her husband Fernando Manrique, 44, to the happiness of their children, Elisa, 11, and Martin, 10, which was singled out at their moving funeral service on Monday.

The siblings, who were autistic, were found dead along with their parents and pet dog in their home in Sydney's north after what police suspect was a deliberate gas poisoning.

But in keeping with the wishes of their grieving relatives, the family of four were farewelled together.

Colourful toys were placed on top of the children's white coffins, while their parents' coffins were covered in white floral arrangements.

Elisa and Martin's love of art was also honoured with a tin of paint brushes and several artworks placed at the altar of the Holy Name Catholic Church in Wahroonga.

"We must now find peace and acceptance in our hearts," the Lutz and Manrique families, most of whom travelled from Colombia last week, said in a statement.

"It is not easy, and the exposure has only exacerbated our pain".

Two wreaths made with Australian and Colombian flora were placed above the coffins to symbolise the families who stood united in their grief, the mass was told.

They said they hoped the tragedy would raise awareness "of the enormous economic, social and psychological stresses that families of children with disabilities bear".

"Whilst science works day after day to comprehend all these different conditions, society cannot remain indifferent to the situations families bear, and needs to move and develop means to support them better," the statement said.

Elisa and Martin both attended St Lucy's School, which caters for children with disabilities, where Maria was considered a "champion for their cause".

The school's acting principal Warren Hopley, who's been in close contact with the Lutz and Manrique relatives since the tragedy, says he admires their compassion for each other.

"They understand that dad must have had a problem here and for nobody's fault he has snapped," he said outside the church.

"But he was a father who loved his children, there's no doubt about that".

"This death hasn't been caused by disability ... but families do need a great deal of support when it comes to a child with intellectual disabilities."

Ms Lutz, Mr Manrique and their two children were cremated in a private service before their remains are returned to Colombia.

Readers seeking support and information about suicide prevention can contact Lifeline on 13 11 14.